# Table 8: J-Curve Robustness Tests (OECD Subsample)

## Test 1: Pre-Trends

Coefficients at h<0 should be insignificant if J-curve is causal.

| Outcome | h=-3 | h=-2 | h=-1 | h=0 | h=1 | h=2 | h=3 |
|---------|------|------|------|-----|-----|-----|-----|
| Investment/GDP | -0.2729 | -0.5237* | -0.8874*** | -1.6546*** | 0.1071 | 0.6917** | 0.2045 |
| GDP Growth | -2.6736*** | -2.3669*** | -1.4518*** | -1.2573*** | 0.4642 | 1.7783** | 1.8344** |
| MPK | 0.0004 | 0.0009 | 0.0021** | -0.0019*** | 0.0052*** | 0.0031*** | 0.0010 |
| Δlog K/L | -0.0019 | -0.0006 | -0.0010 | 0.0064*** | -0.0060* | -0.0157*** | -0.0138*** |

## Test 2: Placebo Instrument (Gravity-Only vs Demographic)

| Outcome | h | Demo β | Demo p | Placebo β | Placebo p |
|---------|---|--------|--------|-----------|----------|
| Investment/GDP | 0 | -1.6546*** | 0.0000 | -0.3543 | 0.3527 |
| Investment/GDP | 1 | 0.1071 | 0.7314 | -0.1094 | 0.7587 |
| Investment/GDP | 2 | 0.6917** | 0.0437 | -0.5469 | 0.1158 |
| Investment/GDP | 3 | 0.2045 | 0.5539 | -0.4767 | 0.1865 |
| Investment/GDP | 4 | -0.3329 | 0.3336 | -0.7808** | 0.0258 |
| Investment/GDP | 5 | -0.5454 | 0.1129 | -1.3440*** | 0.0001 |
| GDP Growth | 0 | -1.2573*** | 0.0000 | -0.1955 | 0.2816 |
| GDP Growth | 1 | 0.4642 | 0.4412 | -1.0756*** | 0.0090 |
| GDP Growth | 2 | 1.7783** | 0.0135 | -2.3253*** | 0.0001 |
| GDP Growth | 3 | 1.8344** | 0.0148 | -1.6402** | 0.0224 |
| GDP Growth | 4 | 0.0104 | 0.9896 | -2.1434*** | 0.0092 |
| GDP Growth | 5 | 0.3055 | 0.7064 | -4.9870*** | 0.0000 |
| MPK | 0 | -0.0019*** | 0.0074 | -0.0002 | 0.8612 |
| MPK | 1 | 0.0052*** | 0.0000 | 0.0073*** | 0.0000 |
| MPK | 2 | 0.0031*** | 0.0045 | 0.0032* | 0.0738 |
| MPK | 3 | 0.0010 | 0.3665 | 0.0058*** | 0.0016 |
| MPK | 4 | -0.0027** | 0.0200 | 0.0032* | 0.0759 |
| MPK | 5 | -0.0018 | 0.1196 | -0.0041** | 0.0283 |
| Δlog K/L | 0 | 0.0064*** | 0.0030 | -0.0038*** | 0.0056 |
| Δlog K/L | 1 | -0.0060* | 0.0769 | -0.0042 | 0.1609 |
| Δlog K/L | 2 | -0.0157*** | 0.0001 | 0.0003 | 0.9477 |
| Δlog K/L | 3 | -0.0138*** | 0.0015 | -0.0059 | 0.2892 |
| Δlog K/L | 4 | -0.0078* | 0.0959 | -0.0090 | 0.1579 |
| Δlog K/L | 5 | -0.0082 | 0.1011 | 0.0059 | 0.3979 |

## Test 3: J-Curve × Rule of Law Interaction

| Outcome | h | Interaction β | p | Base β | RoL β |
|---------|---|--------------|---|--------|-------|
| Investment/GDP | 0 | 0.3003 | 0.5098 | -1.9622 | -2.0427 |
| Investment/GDP | 1 | 0.5225 | 0.2694 | -0.4472 | -1.3317 |
| Investment/GDP | 2 | -0.1481 | 0.7759 | 0.8297 | 1.0125 |
| Investment/GDP | 3 | 0.1974 | 0.7071 | -0.0447 | -1.0602 |
| Investment/GDP | 4 | 0.3896 | 0.4548 | -0.8030 | -1.0629 |
| Investment/GDP | 5 | 0.6467 | 0.2119 | -1.2270 | -1.5435 |
| GDP Growth | 0 | 1.5780*** | 0.0009 | -3.1938 | -8.0202 |
| GDP Growth | 1 | 1.7863* | 0.0544 | -1.5510 | -7.5598 |
| GDP Growth | 2 | 1.2069 | 0.2701 | 0.2910 | -5.1031 |
| GDP Growth | 3 | 0.7967 | 0.4860 | 0.8546 | -3.2322 |
| GDP Growth | 4 | 1.7311 | 0.1543 | -1.9809 | -5.2012 |
| GDP Growth | 5 | 2.4585** | 0.0462 | -2.5413 | -11.2822 |
| MPK | 0 | -0.0003 | 0.7803 | -0.0016 | -0.0032 |
| MPK | 1 | -0.0005 | 0.7710 | 0.0058 | 0.0008 |
| MPK | 2 | -0.0027* | 0.0971 | 0.0063 | 0.0123 |
| MPK | 3 | -0.0011 | 0.5119 | 0.0023 | -0.0016 |
| MPK | 4 | 0.0008 | 0.6149 | -0.0035 | -0.0004 |
| MPK | 5 | 0.0012 | 0.5079 | -0.0033 | -0.0059 |
| Δlog K/L | 0 | -0.0003 | 0.9237 | 0.0077 | 0.0039 |
| Δlog K/L | 1 | -0.0040 | 0.4433 | -0.0018 | 0.0216 |
| Δlog K/L | 2 | -0.0022 | 0.7180 | -0.0138 | 0.0143 |
| Δlog K/L | 3 | 0.0012 | 0.8555 | -0.0155 | 0.0083 |
| Δlog K/L | 4 | -0.0015 | 0.8298 | -0.0067 | 0.0173 |
| Δlog K/L | 5 | -0.0016 | 0.8328 | -0.0073 | 0.0214 |

## Test 4: Dose-Response (High vs Low Demographic Inflows)

| Outcome | h | High β | High p | Low β | Low p |
|---------|---|--------|--------|-------|-------|
| Investment/GDP | 0 | -0.4957 | 0.2966 | -2.8248*** | 0.0000 |
| Investment/GDP | 1 | 0.4585 | 0.3414 | -0.2507 | 0.5209 |
| Investment/GDP | 2 | 0.9024* | 0.0847 | 0.7136* | 0.0917 |
| Investment/GDP | 3 | 0.6710 | 0.2057 | -0.0239 | 0.9550 |
| Investment/GDP | 4 | 0.3715 | 0.4760 | -0.8129** | 0.0493 |
| Investment/GDP | 5 | 0.2039 | 0.7037 | -1.0880*** | 0.0080 |
| GDP Growth | 0 | -0.6569** | 0.0434 | -1.8306*** | 0.0001 |
| GDP Growth | 1 | 0.4525 | 0.5226 | -0.4751 | 0.6046 |
| GDP Growth | 2 | 0.9783 | 0.2656 | 1.7546 | 0.1147 |
| GDP Growth | 3 | 1.1472 | 0.2247 | 1.7667 | 0.1284 |
| GDP Growth | 4 | -0.0532 | 0.9589 | -0.4164 | 0.7341 |
| GDP Growth | 5 | -0.2042 | 0.8408 | -0.0427 | 0.9729 |
| MPK | 0 | -0.0021* | 0.0555 | -0.0017* | 0.0627 |
| MPK | 1 | 0.0076*** | 0.0000 | 0.0033*** | 0.0063 |
| MPK | 2 | 0.0034* | 0.0756 | 0.0029** | 0.0191 |
| MPK | 3 | 0.0005 | 0.8156 | 0.0015 | 0.2514 |
| MPK | 4 | -0.0031* | 0.0993 | -0.0020 | 0.1244 |
| MPK | 5 | -0.0025 | 0.1865 | -0.0017 | 0.2299 |
| Δlog K/L | 0 | 0.0065** | 0.0124 | 0.0051 | 0.1215 |
| Δlog K/L | 1 | -0.0054 | 0.1710 | -0.0063 | 0.2431 |
| Δlog K/L | 2 | -0.0117*** | 0.0090 | -0.0195*** | 0.0031 |
| Δlog K/L | 3 | -0.0073 | 0.1441 | -0.0210*** | 0.0033 |
| Δlog K/L | 4 | 0.0006 | 0.9096 | -0.0159** | 0.0395 |
| Δlog K/L | 5 | -0.0041 | 0.4112 | -0.0127 | 0.1435 |

*p<0.1, **p<0.05, ***p<0.01. OECD subsample. PanelGLS with AR(1).*
